Methods of plugging and abandoning a well and, more particularly, methods of using extended-life cement compositions comprising calcium aluminate cement to plug and abandon a well are provided.
Cement compositions may be used in a variety of subterranean operations. In some instances, extended-life cement compositions have been used. In contrast to conventional cement compositions that set and harden upon preparation, extended-life cement compositions are characterized by being capable of remaining in a pumpable fluid state for about one day or longer (e.g., about 7 days, about 2 weeks, about 2 years or more) at room temperature (e.g., about 80° F.) in storage. When desired for use, the extended-life cement compositions should be capable of activation and consequently develop reasonable compressive strengths. For example, an extended-life cement composition that is activated may set into a hardened mass. Among other things, extended-life cement compositions may be suitable for use in operations where it is desirable to prepare the cement composition in advance. This may allow the extended-life cement composition to be stored prior to use. In addition, this may allow the extended-life cement composition to be prepared at a convenient location before transportation to the job site. Accordingly, capital expenditures may be reduced due to a reduction in the need for on-site bulk storage and mixing equipment. This may be particularly useful for offshore operations where space onboard the vessels may be limited.
In cementing methods, such as plug-and-abandon operations, a plug may be formed in a wellbore to seal off the wellbore for abandonment. In performing plug-and-abandon operations, a cement composition may be placed in the wellbore at a desired depth. The cement composition should set in the wellbore, forming a hardened mass (e.g., a plug) that seals off selected intervals of the wellbore. The mass may prevent and/or reduce zonal communication and migration of fluids that may contaminate water-containing formations. It may desirable in certain instances to form one or more plugs in the wellbore adjacent to hydrocarbon-producing formations and water-containing formations.
In conventional offshore plug-and-abandon operations, equipment may be used to prepare the plugging composition and to separate the raw materials. This equipment may be transported to the offshore facility and the equipment can require additional personnel to operate. These additional requirements can increase expenditures and operation